The present invention relates to a method for producing a component connection of first and second components via a ball as a connecting part.
From the prior art, a large number of component connections are known in which balls are used as connection elements. For example, DE 10 2009 049 602 B3 discloses a “component connection” in which there is welded to a bodywork sheet a ball which acts as a connection element and which engages in a positive-locking manner in a recess which is provided in another sheet.
DE 10 2012 214 453 discloses a component connection in which a “dual ball”, that is to say, a connection element which is formed by two balls which are connected to each other, is welded to a sheet, wherein a clip element can be clip-fitted to the dual ball.
An object of the invention is to provide a method for producing a component connection which has a dual ball or a multiple ball, which method opens up other application fields.
This and other objects are achieved according to the invention by a method for producing a component connection that includes the follow steps: providing a first component; providing a first ball; pressing the first ball against the first component by use of a sonotrode; causing the first ball to vibrate by use of the sonotrode in such a manner that material of the first ball and/or material of the first component melts and welds the first ball to the first component; providing a second ball; pressing the second ball against the first ball by use of the same or another sonotrode; causing the second ball to vibrate by use of the same or another sonotrode in such a manner that material of the second ball and/or material of the first ball melts and the second ball is welded to the first ball.
The starting point of the method according to the invention for producing a component connection is a substrate which is referred to below as the “first component”. The first component may, for example, be planar or have almost any other form.
The first component is at least in the region of a portion of the surface thereof produced from thermoplastic plastics material. Of course, the entire first component may be produced completely from thermoplastic plastics material. Alternatively, the first component may be produced completely or partially from a fiber-reinforced thermoplastic plastics material. The fibers are then distributed inside the thermoplastic plastics material of the first component and are used for reinforcing or strengthening. It is possible to consider as strengthening fibers, for example, carbon fibers, glass fibers, aramid fibers or the like. With regard to the fiber length thereof, long fibers, short fibers or so-called endless fibers or combinations thereof can be used.
As already indicated, the entire first component does not have to completely be made of thermoplastic plastics material. It is also contemplated for the first component to have a carrier substrate which is coated completely or at least in a part-region of the surface thereof with a thermoplastic plastics material or a fiber-reinforced thermoplastic plastics material.
According to the invention, a first ball is connected to the first component by use of ultrasonic welding. To this end, a first ball which is provided is pressed by a sonotrode against a “connection location” of the first component.
The first ball may be a ball which completely comprises thermoplastic plastics material. Alternatively, it may also be a hollow ball which comprises a thermoplastic plastics material. It is further contemplated for the first ball to have a ball core which, for example, may comprise steel, aluminum, glass, lead or the like and which is coated or covered completely or partially with a thermoplastic plastics material or a fiber-reinforced thermoplastic plastics material. In this manner, specific properties of the ball core which may, for example, be magnetic, can be combined with the specific properties of the thermoplastic plastics material which is used as a “coating” (for example, weldability to components or substrates).
If at least the surface or a portion of the surface of the first ball comprises a fiber-reinforced or particle-reinforced plastics material, the strength of the first ball can thereby be increased.
Using the sonotrode, the first ball which is pressed onto the first component is caused to vibrate which leads to material of the first ball and/or material of the first component melting locally, that is to say, all the way around the contact location. Thus, the first ball locally welds to the first component.
According to the invention, a second ball is welded onto the first ball. To this end, the second ball is first pressed by way of the same sonotrode or another sonotrode against the first ball and caused to vibrate which leads to material of the second ball and/or the material of the first ball melting in the contact region, that is to say, all the way around the contact location. Thus the second ball welds to the first ball.
According to the invention, it is of course possible to produce not only dual balls but also quite generally multiple balls, that is to say, connection elements which have two or more than two balls which are welded to each other sequentially one after the other.
The individual balls which are intended to be welded to each other may be identical or different with respect to their structure. For example, the second ball may be a solid ball which is produced from thermoplastic plastics material or a hollow ball which is produced from thermoplastic plastics material. Alternatively, the second ball may have a ball core which is made of, for example, steel, aluminum, glass, lead or the like and which is completely or partially coated or covered with a thermoplastic plastics material or a fiber-reinforced thermoplastic plastics material. As already explained above in connection with the first ball, specific properties of the ball core can thereby be combined with specific properties of the coating.
In order to facilitate the pressing and positioning of the second ball on the first ball or with respect to the first ball, a positioning aid can be used. The term “positioning aid” is intended quite generally to be understood to mean a device which partially or completely engages round the first ball and which acts as a guide for precise guiding of the sonotrode or the second ball which is intended to be pressed thereby onto the first ball. In other words, the positioning aid is thus initially placed on the first ball, wherein the positioning aid at least partially engages round the first ball. Subsequently, the sonotrode is guided or positioned by the positioning aid when the second ball is pressed onto the first ball.
The same or a similar positioning aid can also already be used when the first ball is pressed onto or welded to the first component. Before the first ball is pressed onto the first component, therefore, a positioning aid is first placed or pressed on the first component. When the positioning aid is located in a defined position, with assistance the sonotrode or the first ball is guided toward the first component by way of the sonotrode and is pressed against the first component.
In order to achieve precise positioning of the first ball with respect to the first component, a physical marking may be provided on or in the surface of the first component. The physical marking may, for example, be constructed as an indentation-like recess, as a through-hole or the like. The first ball protrudes at least a little way into the physical marking and is thereby clearly positioned relative to the first component.
According to a development of the invention, there is provision for the first or the second ball during the welding operation to be caused to vibrate in a translational manner by way of the sonotrode. Alternatively or additionally, there may also be provision for the first or second ball to be caused to vibrate in a torsional manner by way of the sonotrode during the welding operation.
A significant advantage which is afforded by the completely symmetrical structure of a ball is that, when a ball is welded, it is always correctly orientated in space. Therefore, the ball which is intended to be welded only has to be correctly positioned but not orientated in a specific manner. As a result of the convex geometry of a ball, during positioning on the first component or when the second ball is placed on the first ball, there is produced a point-like contact or a substantially point-like contact. This leads to very high energy densities during the welding operation and consequently to a cleaner locally limited melting of the ball material or the material of the first component. As a result, there is consequently produced a qualitatively very high-grade weld connection.
According to a development of the invention, the first or second ball is sucked or drawn onto or into an indentation-like recess of the sonotrode by use of a suction device. In the sucked-in or drawn-in state, the ball is pressed by way of the sonotrode onto the first component or onto the first ball.
The indentation-like recess may in particular be constructed in the form of a ball joint (socket). The radius of curvature of the ball-joint-like recess of the sonotrode may be equal to the radius of the ball. Relative thereto, the radius of curvature of the ball-joint-like recess may be slightly smaller than the radius of the ball, which then leads to annular contact between the ball-like recess and the ball. If the radius of curvature of the ball-joint-like recess is slightly larger than the radius of the ball, the ball is in abutment with the ball-joint-like recess only in the region of a relatively small contact face.
There may be provision for the first or second ball to be removed by way of suction using the suction device from a ball reservoir, in particular from a storage container which is filled with a large number of balls, sucked onto the sonotrode and by way of the sonotrode guided toward and pressed onto the first component or the first ball.
Alternatively, there may also be provision for the ball to be supplied to the sonotrode or the recess of the sonotrode by way of a supply device (for example, pneumatically by means of a supply hose or the like), for example, from the side.
According to a development of the invention, a clip element is clip-fitted to the first and/or the second ball. The clip element may be an integral part of a second component.
For such a component connection, there are almost unlimited application possibilities. The invention is particularly suitable for vehicle bodywork construction, that is to say, the first and/or the second component may, for example, be a vehicle bodywork component. Alternatively, the first or the second component may be a vehicle bodywork component and the other component may be a fitted component. Such fitted components may, for example, occur in very large numbers in the engine compartment region of vehicles, but also in other regions of the vehicle, such as, for example, in the trunk space, in the underfloor region or the like.
Using such a clip element, a second component which has holes may also be connected to the first component in a positive-locking and/or non-positive-locking manner. The second component which is provided with a through-hole can thus be positioned on the first component in such a manner that the “dual ball” which is formed by the two balls protrudes through the hole which is provided in the second component. In order to fix the two components, only one clip element then has to be clip-fitted to the “dual ball” which then acts as a connection element for the two components.
The welding of the balls can be carried out manually, that is to say, by way of a sonotrode which is intended to be guided and actuated by hand, or in a fully automated manner. With an automated process, the sonotrode is guided, for example, by use of an industrial robot.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.